The past few years has witnessed the ever-increasing availability of relatively inexpensive, low power wireless data communication services, networks and devices, promising near wire speed transmission and reliability. One technology in particular, described in the IEEE Standard 802.11b-1999 Supplement to the ANSI/IEEE Standard 802.11, 1999 edition, collectively incorporated herein fully by reference, and more commonly referred to as “802.11b” or “WiFi”, has become the darling of the information technology industry and computer enthusiasts alike as a wired LAN/WAN alternative (because of its potential 11 Mbps effective data transmission rate, ease of installation and use, and transceiver component costs make it a real and convenient alternative to wired 10 BaseT Ethernet and other cabled data networking alternatives. With 802.11b, workgroup-sized wireless LAN networks can now be deployed in a building in minutes, a campus in days instead of weeks since the demanding task of pulling cable and wiring existing structures is eliminated. Moreover, 802.11b compliant wireless networking equipment is backwards compatible with the earlier 802.11 1 M/2 Mbps standard, thereby further reducing deployment costs in legacy wireless systems.
More recently, even faster effective data throughput has been achieved with deployment of next generation wireless LAN communications devices, including access points and client adaptors, compliant with IEEE Standard 802.11a (1999) and DRAFT IEEE Standard 802.11g (2002) High Rate PHY Supplements to the ANSI/IEEE Standard 802.11, 1999 edition, also collectively incorporated herein fully by reference.
To date, wireless LAN client adaptors for the 802.11 family (including adaptors compliant with the base 802.11, 802.11b, 802.11a and 802.11g standards), which provide wireless LAN communications functionality to an individual computer, have been packaged in one of five general ways. FIG. 1 shows a wireless LAN client adapter 101 packaged in a removable PC Card or PCMCIA form factor. When fully inserted (interface 103 first) into a peripheral slot such as a PC Card or PCMCIA slot on a compatible host computer, such as a laptop, network appliance, or PDA, the antenna portion 102 is designed to extend from the end of the slot and beyond the computer case perimeter. This configuration enhances adaptor RF performance, and ultimately effective bandwidth and communications link quality since the antenna 102 is placed outside the RF damping effects of a typically metallic card receiver within the computer (not shown), computer chassis (not shown), and RF shielding used to attenuate RF radiation created by internal computer components such as the information processing system (e.g. a CPU or microprocessor). In other words, the external positioning of antenna 102 avoids the Faraday cage effects of the computer card receiver and/or chassis, as well as reduce component-generated RF interference since the RF shielding, being contained within the computer case, is inherently positioned between the antenna 102 and the RF radiating components. Following pressures to make electronic devices smaller and more power efficient, wireless LAN client adaptors have been recently introduced which generally follow the configuration shown in FIG. 1 but have smaller overall form factor, such as those specified for removable insertion into Compact Flash (aka CF-Card), Smartmedia, Secure Digital (SD) or MultiMedia Card (MMC) compatible peripheral slots being introduced on the newest computers and intelligent devices.
Due to the popularity of the PC Card package shown in FIG. 1, as well as competitive pressures to re-use designs where practicable, another configuration alternative is presented in FIG. 2 which is suitable for deployment in desktop computers. This configuration includes the PC card wireless LAN adaptor 101 mated to a PCI daughtercard 201 for removable insertion into a PCI slot (not shown) found on most desktop system boards or motherboards. In particular, the card edge interface 202 and the PCI glue logic 204 is used to bridge communications between the PCI bus of a desktop computer hosting the adaptor and the PC Card interface 103 fitted to card receiver 206. The metal card guide 208 is used to secure the daughtercard 201 including the wireless LAN adaptor 101 firmly into the PCI slot and within the desktop computer housing (not shown). As in FIG. 1, the antenna 102 is designed to be positioned external to the daughtercard 201 and the computer case when the adaptor 101 is fully inserted into the receiver 103 to maximize potential RF performance.
With respect to the wireless LAN adaptor configurations shown in FIGS. 1 and 2, the following apparent shortcomings are noted. First, in both configurations, the antenna 102 is in a fixed position external to the computer and case into which the adaptor is inserted. This limits antenna positioning options, as the whole host computer, not the antenna must be reoriented. This is particularly disadvantageous when the host computer adopts a desktop form factor, including a mini-tower or full tower chassis, which, because of its bulk, lends itself to placement on a floor underneath a desk, table or other work surface and often in a corner. This, in turn, positions the typically rear-facing antenna in a far from ideal RF reception environment. Moreover, since the antenna 102 extends from the protective computer case, it is subject to impact damage and stress, and actually alters the form factor of the computer hosting the adaptor, making it harder to carry or fit within tight spaces. Finally, such packaging unnecessarily adds costs, particularly with respect to the configuration shown in FIG. 2, since two distinct types of interfaces must be supported, along with artificially imposed constraints on the wireless adaptor 102 form factor.
Responsive to these shortcomings, a third wireless LAN adaptor alternative has been introduced and is generally depicted in FIG. 3. In this configuration, the entire wireless LAN adaptor 302 is packaged as a self-contained unit external to the computer (not shown) it is servicing. A universal serial bus connection via plug 306 is used to enable high speed communication between the adaptor 302 and the computer. This configuration permits easy repositioning or reorientation of a movable antenna 304, as well as the adaptor 302 itself, and does not detract from the host computer's form factor or portability, the latter assuming the adaptor 302 is unplugged prior to transport. Further, this adaptor 302 can easily interface with and support any computer supporting USB, including USB 1.1, USB 2.0, and USB On-The-Go.
However, the standalone configuration shown in FIG. 3 requires a robust and protective housing 305, which adds cost, and takes up additional space, and actually becomes a separate article to manage for the clutter conscious. Further, due to the strict power draw requirements present in these USB standards, this configuration may need to draw power from an external power supply to maintain acceptable operating range, thereby further adding to clutter and installation inconvenience over other known adaptor configurations.
FIG. 11 illustrates a fourth known wireless LAN adaptor configuration 1100. This configuration is generally similar to the configuration 200 shown in FIG. 2 and is also particularly suited for use in desktop computer systems. As such, PCI glue logic 204 is used to bridge communications between the host computer and the wireless LAN adaptor components, but in this case, the PC Card interface 103 is eliminated and the baseband processor 1112 and RF transceiver unit ICs 1110 comprising the wireless LAN adapter unit electronics are disposed directed on the daughtercard 1120. Like the configuration shown in FIG. 2, the baseband processor and transceiver electronics remain protected by the computer housing when the daughtercard 1120 is secured therein.
However, in this alternative, an external antenna unit 102 is physically removed from the daughtercard but remains RF coupled thereto through a coaxial cable 1104 removably secured to a cable interface 1114 shown here extending through the guide 208. In so doing, the antenna unit 1102 can be repositioned or reoriented to improve wireless link quality, yet the transceiver components remain protected and shield by the enveloping computer casing and chassis, unlike the configuration alternative shown in FIG. 3.
In view of the external antenna unit 1102 and cabling unit 1104, this solution, like the configuration shown in FIG. 3, adds to clutter and installation inconvenience. Moreover, this configuration is not believed practical in cost sensitive applications, since, at the very least, a relatively expensive external antenna unit 1102, a durable coaxial cabling 1104 and a cable interface 1114 must now be additionally included as part of the adaptor parts, and consequently presents increased manufacturing and assembly complexity.
Finally, some of the latest computer designs offer integrated wireless LAN capabilities, typically through coupling transceiver and baseband processor electronics on the computer motherboard or on a proprietary or mini-PCI daughtercard with an antenna disposed on or integrated within the computer case. Like FIG. 11, a coaxial cable is used to RF couple the RF transceiver electronics to the antenna. While performance is generally superior, this type of configuration is typically customized to the particular computer in which it is designed to operate and is thus limited to those buying such computers. Upgrade options are limited. Moreover, these solutions are relatively costly compared with more traditional configurations highlighted above.